#header {
    height: 80px;
    background-color: #f0f0f0;
  }
  #system-name {
    float: left;
    height: 80px;
    display: flex;
    align-items: center; /* 垂直居中 */
    margin-right: 60%;
  }
  
  #system-name span:first-child {
    margin-right: 10px; /* 控制图片与文本之间的间距 */
  }
  #system-name img {
    width: 50px; /* 设置图片的宽度为50像素 */
    height: auto; /* 高度自适应 */
    margin-right: 10px; /* 可以添加一些 margin 属性来控制图片与文本之间的间距 */
  }
  #admin-info{
    height: 80px;
    display: flex;
    align-items: center;
  }
  #admin-info img {
    width: 50px;
    height: 50px;
    margin-right: 10px;
    border-radius: 50%;
  }
  #admin-info button {
    background-color: #f0f0f0;
    border: none;
    padding: 10px 20px;
    font-size: 16px;
    cursor: pointer;
  }

  #aside {
    width: 20%;
    float: left;
    height: 550px;
    background-color: #f5f5f5;
  }
  #container {
    width: 80%;
    height: 550px;
    float:right;
  }
  #main {
    width: 100%;
    float: right;
    height: 470px;
    background-color: #ffffff;
  }
  #footer {
    clear: both;
    height: 80px;
    background-color: #f0f0f0;
  }

  nav {
    margin-top: 20px;
    padding-left: 0;
    background-color: #f5f5f5;
  }
  
  nav ul {
    list-style: none;
    margin: 0;
    padding: 0;
  }
  
  nav ul li {
    position: relative;
    display: block;
  }
  
  nav ul li > a {
    display: block;
    padding: 15px;
    text-decoration: none;
    color: #333;
  }
  
  nav ul li:hover > a {
    background-color: #eaeaea;
  }
  
  nav ul ul {
    display: none;
    position: absolute;
    top: 0;
    left: 100%;
    background-color: #f5f5f5;
    border-left: 1px solid #ccc;
    width: 200px;
  }
  
  nav ul li:hover > ul {
    display: block;
  }
  
  nav ul ul li {
    position: relative;
    display: block;
  }
  
  nav ul ul li > a {
    display: block;
    padding: 10px 15px;
    text-decoration: none;
    color: #333;
  }
  
  nav ul ul li:hover > a {
    background-color: #eaeaea;
  }
  
  nav ul ul ul {
    display: none;
    position: absolute;
    top: 0;
    left: 100%;
    background-color: #f5f5f5;
    border-left: 1px solid #ccc;
    width: 200px;
  }
  
  nav ul ul li:hover > ul {
    display: block;
  }
  
  nav ul li.active > a {
    background-color: #ccc;
    color: #fff;
  }
  
  nav ul ul li.active > a {
    background-color: #aaa;
    color: #fff;
  }